ESI Spectrograph Electronics Manual
Maintenance:
The following is an index of the covered maintenance procedures:
1. Access to the Lantronix port connectors 2. High altitude brushes 3. Changing calibration or flat field lamps 4. Shutter operation and testing
Access to the Lantronix port connectors:
The Lantronix box is mounted on the bottom plate next to the cooling fans. It is mounted with it's indicator lights pointing out from the locker. This makes it easier for troubleshooting. Unfortunately, it makes it harder to plug into the port connectors. If you need to connect cables to the box it will be easier to either use an inspection mirror and flashlight or to take the box out of it's mounting strap. To take the box off loosen the screw on the left-hand side of the box and then remove the screw from the side of the bracket next to the cooling fans.
Each of the servomotors has high altitude brushes installed. These brushes are used to help keep radiated noise low. The brushes are made from a softer material so replacement may become necessary in time. To do so you must locate the servomotor and disconnect the power leads. Next, unscrew the black brush retaining plug. The brushes are spring loaded so be careful not to drop or lose the threaded plug. Now, install the new brushes, replace the retaining plug and reconnect the power leads. The RJ-45 connectors can now be accessed by flipping the box over.
Changing calibration or flat field lamps:
To change any of the internal lamps, the instrument has to be off of the telescope so that you can both open electronics locker #3 and in the case of the HgNe or Xenon, remove the calibration lamp housing from the instrument. The Neon and Quartz lamps may be reached by removing several of the access panels near and to the top of locker #3. The CuAr lamp is accessible inside of the locker.
Copper-Argon lamp:
To replace the copper hollow cathode lamp, first disconnect power from locker #3 and remove the cover. At the top of the box, locate the black fiber bundle that exits the locker and trace it back to the copper lamp box. The box is also obvious by the fact that it is perforated with large holes for air flow. Remove the four red thumbscrews at the end opposite the fiber bundle to remove the lamp. Replace the lamp, thumbscrews, and then restore power to the locker and test the lamp. Caution, the lamp emits UV and should not be looked directly at without eye protection.
Replacing the Quartz or Neon lamp:
Remove power from electronics locker #3. To get to either lamp, remove the access panels near the top left-hand side of the locker. The calibration lamp housing is located above the locker inside the instrument. Carefully remove the foam insulation around the tube to expose the quartz or neon lamp mounting block. Each of these mounting blocks is secured to the tube with red thumbscrews. Remove the appropriate screws and pull the block straight out. For the quartz lamp, simply pull the lamp out of the socket. Note: these lamps burn very hot and even a partial fingerprint on the envelope could cause uneven heating resulting in a fracture and failure of the lamp. We suggest that when replacing this lamp that you only handle the lamp with it in it's protective plastic wrapper. If you can't avoid touching the lamp itself, use a tissue or cloth saturated with alcohol to clean it off.
Replacing the Xenon or HgAr lamp:
Removing the Calibration Lamp Housing:
To safely change the grid lamps you must first remove the calibration lamp housing from the spectrograph. This job should be performed by at least two people. The first step is to remove power to electronics locker #3. Next, remove it's cover and disconnect all of the cables that exit the locker and run through the return air cooling duct located in the upper left-hand corner of the locker. The connectors include four High-Voltage inline connectors, a two pin inline connector for the Pen-Ray Neon lamp, a two pin inline connector for the quartz lamp, and a two pin inline connector for the temperature sensor. Each lamp and the temperature sensor have either unique connectors or in the case of the HV connectors unique genders. There are three extra connectors that are the same as the Pen-Ray connector. These are essentially spares that are available for future use but originally in place for an earlier lamp configuration. Note that these cables are labeled and that the neon lamp should be connect to the cable labeled 'NEON 1."
With the cables disconnected, remove the instrument access panels near and around the top of locker #3. Carefully pull both the inlet and outlet air ducts from the flanges located on the locker. Loosen the set screw that secures the fiber bundle front of the housing (left side as seen facing the electronics locker.) Gently pull the fiber bundle away from the housing. Remove the four screws that mount the housing to the framework of the instrument and carefully remove the housing from the instrument remembering that the housing contains optical elements.
Changing the grid lamps:
With the housing on a bench, remove the three screws around the rear perimeter of the housing. Carefully pull on the rear plate to gain access to the grid lamps. Disconnect the inline
High-Voltage connectors from the grid lamps. These are again set up so that they can not be connected to the wrong wires, i.e. one lamp uses two female connectors and the other uses male connectors.
Remove the screws that hold the xenon lamp to the standoffs. If you are replacing the HgAr, remove the top standoffs so that you can remove the lamp.
Reassembly:
To reassemble the system reverse these procedures. As you start, try to keep the foam insulation intact as much as possible. Its hard to work on once the housing is back in the instrument.
- Mount lamp assembly to instrument frame member
- Reconnect air inlet tube to flange on locker.
- Pass cables through outlet flange and into locker.
- Reconnect air tube to flange on locker.
- Insert fiber bundle into mounting ring on front of the housing and lightly tighten set screw.
- Inside locker #3, reconnect cables:
- HgAr, 2 high-voltage inline connectors
- Xenon, 2 high-voltage inline connectors
- Neon, 2-pin inline cord labeled 'Neon 1'
- Quartz, 2-pin inline connector
- Temperature sensor, 2-pin inline connector
- Close locker and turn on power.
Shutter operation and testing:
(See EL-1233 write-up in the Miscellaneous Drawings section of the manual)
